Control for air conditioning systems



March l, 1938. M. F; RATHER CONTROL FOR AIR CONDITIONING SYSTEMS Filed July 17, 1936 2 Sheets-SheetI 1 Snnentor @flauwe/@Bgm Q, @4f-..

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CONTROL FOR AIR CONDITIONING SYSTEMS Y Filed July 17, 1936 2 Sheets-Sheet 2 suMMERfwINn-ma. 2 (2 THERMOSTAT I I'O ZONE A.

Am CONDITIONING UNIT omnooa, SUMMER-WINTER. THEKMos'rAT 4 5 42 THERMOSTAT y v Gttorneg's Patented Mar. l, 1938 coN'rRoL Fon AIR CONDITIONING SYSTEMS f Maxwell F. Rather, Cleveland, Ohio,

Johnson Service Company,

assignor to Milwaukee, Wis., a

corporation of Wisconsin v Application July 17, 193s, serial No. 91,247

' 9 Claims.

This invention relates to air conditioning and particularly to systems where a single conditioner supplies conditioned air to two` zones.

In installations of this type the demands made for conditioned air by the two zones vary relatively to one another from time to time so that in order to apply the output of the conditioner to best eiect it is necessary to divide the output directed to the two zones in varying proportions.

One object of the present invention is to divide the output under the control of the differential in condition in the two zones. Temperature will be assumed as the controlling condition for purpose of explanation.

Modern year round conditioning systems operate reversely under winter and summer conditions. Generally stated they heat and humidity in winter and cool and dehumidify in summer. Where control is by regulating the flow of conditioned air to the two zones the control must be reversed for the two seasons. For example, if

temperature diierential be adopted as the controlling factor a fall of temperature would be.,

corrected by an increase in the flow of conditioned air, whereas in .summer a fall would be corrected by a. decrease. This implies a reversal of`--the proportioning action. To meet this requirement the present invention providesfora reversal of the dierential effect as between winter and summer conditions.

As a refinement, means responsive to Voutdoor conditions (usually temperature) are provided to eifect the reversal as suchtemperaturevpasses above and below a chosen value.

It should be. observed that this invention is not concerned with control of the total perfomance of the conditioner, but rather with proportioning the total output. between zones or points of use. Hence to simplify the description it will be assumed that the conditioner has a constant out? put, though that -condition is` not essential. In other words the invention does not inhibit the use of means to regulate the total performance of the conditioner, but is not directly concerned with such means.

Practical embodiments of the invention will now be described with reference to the accompanying drawings, in which,- I

Fig. 1 is a diagrammatic plan view, largely in4 section, showing the control applied to a single year-round conditioner serving two zones.

Fig. 2 is a similar view showing an equivalent system using a different type of thernostat.

Figs. 3 and 4 show the system of Fig. 1 modied by the substitution of a single multiple way cock (Cl. 23e-1) for the two simultaneously operated three-way poppet valves used in the structure of Fig. 1.

Fig. 5 shows an alternative damper structure which can be used with the structures of Figs. 1 and 2. x Referring first to Fig. '1, Al5 represents conditioning means for heating (and if desired humidifying) air passing through it in Winter, and lfor cooling and dehumidifying air passing through it in summer..- Its construction and mode of operation are immaterial so long as it has these alternative functions. A circulating fan is normally included in such a conditioner but is not illustrated as a distinct element.

A branch 'l delivers conditioned air to one zone l A and a branch 8 delivers conditioned fair to the other zone B: AL` splitter damper 9 urged to its neutral or mid-position by spring I may be shifted to vary the relative proportions sent to zone A and zone B of the total conditioned air available. Manually adjustable louver dampers |2 control the amount of fresh air drawn into the conditiener. Other manually operable dampers I3 are closed when the conditioner is operating, but may be open when the system operates merely to venL tilate vand the conditioner is out of action.

A return duct Il leads back to-conditioner 6 Y from zone A and a return duct I5 from zone B. Mounted in these ducts are intermediate acting (sometimes called progressively acting) pneumatic 'thermostats IS and I'l. These thermostats sense Athe temperature in the respective zones,

and location on the return ducts` is well recog-A nized in -the -art as the approximate lequivalent of location in the zone itsel The damper s is actuated tnroughinnk la and lever4|9 by two opposed diaphragm motors whose diaphragme appear at 2| and 22. The diaphragms operate through a thrust member 23 pivoted to lever I9. They are sustained by housing 2l to which lever I9 is pivoted and their working spaces are enclosed by caps ,25;

The thermostats I6 and Il receive air through supply line 26 and in response .to similar variations of temperature establish similarly varying pressures in their branch lines 21 and 28. Each nections to valves 29 and 3| are such that when line 21 is connected to the Working space of diaphragm 2| line 28 is connected to the working space of diaphragm 22, and vice versa.

A manually operable multiple Way valve 35 connects line 34 selectively to supply line 26, via branch 36 (summer setting) or to atmosphere via port 31 (winter setting) or to the branch line 38 of a. positive acting outdoor thermostat 39 which receives its air supply from supply line 26. This last is the automatic setting and when outdoor temperature is above a chosen value, say 70 thermostat 39 puts line 34 under pressure to establish summer conditions, while when outdoor temperature is below '10 it vents line 34 to establish winter conditions.

The operation of the system above outlined is as follows:

If the system is operating under winter conditions, at which time the conditioning unit would be furnishing heated air, the damper 9 will operate to divert more air to whichever of the zones is at the lower temperature and send equal quantities of air to the two zones if they are at the same temperature.

On the other hand, if the system is operating under summer conditions the operation of .the damper will be exactly the reverse of that just described, that is it would send more air to whichever of the two zones is at the higher temperature. It will be observed that the two thermostats I6 and I1 operate as a differential thermostatic controller responsive to the temperature difference between the two zones.

Various other differential thermostatic arrangements might be evolved, and they fall within the broad scope of the invention. Turning now to Fig. 2, the parts identified by the reference numerals 6 to I5 inclusive are the same as before, and so far as they are visible in the drawings, are given similar reference numerals with the letter a. Instead of the thermostats I6 and I1 use is made of two convertible summer-winter thermostats, the thermostat |6a being mounted in the zone A and the thermostat |1a -in zone B. They might equally well be mounted in the return ducts in a manner similar to that shown in Fig. 1.

The thermostats |670. and I'Ia are of the type described and claimed in the patent to Otto, No. 2,021,263, November 19, 1935, and illustrated in detail in Fig. 1 of that patent.4 Generally stated, they include two reversely acting thermostatic elements, one to control heating and the other to control cooling by regulating the leak port which exercises its control through the progressive relay. Selection between the two thermostatic units in each thermostat is made by changing the pressure of the air supplied to the thermostat.

Since the thermostats themselves effect the necessary reversal by selection between the two thermostatic units, it is unnecessary to reverse their connections to the diaphragm motor. Consequently the branch line 21a of thermostat Ilia is connected to the working space of diaphragm 2Ia and the branch line 28a. of the thermostat |1a is connected to the working space of the diaphragm 22a. The diaphragm motor comprising the parts |8a. to 25a is identical with the diaphragm motor having similarly numbered parts in Fig. 1.

To perform the selection a three-way valve 4| is operated by a motor 42 to connect selectively with the supply line 26a. leading -to the two thermostats, either of two pressure' sources,l a.

ter damper.

source 43 at say |1 pounds gage, or a source 44 at say I3 pounds gage. The change in the supply pressure, as will be understood, performs the selection between the winter thermostatic element and the summer thermostatic element, of the thermostats |60. and |1a, shifting them so that both are set for summer conditions or both are set for winter conditions, as the case may be.

The motor 42 is connected to the branch line 45 of an outdoor positive acting thermostat 46 which receives its pressure supply from the source 43. As the outdoor temperature passes a chosen value, say 70, the thermostat 46 either places the motor 42 under pressure or vents the pressure from the motor, sluiting the valve 4| to change the supply of pressure to the summer-winter thermostats. The action of this device is the same as that already described.

The shift from summer to Winter conditions is made by substituting reversely arranged thermostatic elements rather than by reversing the connections of the thermostats to the differential motor, but the differential action is present, as

before, and the effect of reversal is exactly the same.

Figs. 3 and 4 show winter and summer conditions ior a modied form of the system shown in Fig. 1. Here a single four-way valve 41 is substituted for the two three-way valves 29 and 3| of Fig. 1. Since the three-way valves 29 and 3| were operated in unison, a single four-way valve can be made to perform the samefunction.

In Figs. 3 and 4 the thermostat I6b corresponds to the thermostat I6 of Fig. 1, and the thermostat |1b corresponds to the thermostat I1 of Fig. 1. The differential diaphragm motor, indicated generally by the numeral 24b applied to the housing, is identical with the motor 24 shown in Fig. 1. The four-way valve 41 may be shifted either manually or by a motor controlled by an outdoor thermostat, not shown. In these gures the parts similar to those shown in Figure l are given similar reference numerals with the letter b throughout.

Fig. 5 illustrates merely the substitution of progressively acting louver dampers for the split-I trol ow to zone A, open as the louver dampersA 9d, which control iiow to zone B, close. Thisreverse action is produced by a connecting link |8c. The differential is developed by a diierential motor 24e, as in the other figures. A spring |Ic urges the various louver dampers to their normal or equal flow conditions.

While a number of diierent embodiments have been illustrated to make clear the fact that the invention is capable of various mechanical expressions, other arrangements too numerous toA mention, are possible within the broad scope of the invention. This contemplates, first, proportioning the flow to two zones in response to a differential of condition between those zones, and, second, such a reversal of the diierential control that it may eiect regulation in two senses, each one of which is inverse with reference to the other.

`While control by temperature diierential is convenient, and is expected to be the commercially most usual form, the principles of the invention are applicable to .control by other atmos pheric conditions variable by the conditioner, such as relative humidity.

What is claimed is,- 1. 'I'he combination of means for supplying `conditioned air to two zones; means for varying The louver dampers 9c, which conthe relative proportions of the total supply of conditioned air delivered to the respective zones; means responsive to the diierential between similar atmospheric conditions'in said two zones for controlling saidvarying means; and means for reversing the effect of said differential on saidA means responsive to the diierential between similar atmospheric conditions in said two zones for controlling said varying' means; means for reversing the effect of said differential on said varying means; and means rresponsive to outdoor temperature and eiective as such temperaturev passes above and below a chosen value` to actuate reversely said reversing means.

3. The combination of means for supplying conditioned air to two zones; means for varying the relative proportions of the total conditioned air delivered to the respective zones; pneumatic thermostats, one subject to the temperature in each zone and each including ,a source of pressure iluid and thermostatic valve means serving to develop a pneumatic pressure which varies in relation to the temperature to which the thermostatic valve means responds; motor means arranged to actuate said varying means and responsive to the differential of said pressures; and means for reversing the effect of said differential on said motor, whereby the proportioning action is reversed with respect to temperature.

4. The combination of means for supplying conditioned air to two zones; means for varying the relative proportions of the total conditioned air delivered to the respective zones; pneumatic thermostats, one subject to the temperature in each zone and each serving to develop a pneumatic pressure which varies in relation vto the temperature to which it responds; motor means arranged to actuate said varying means and responsive to the differential of said pressures;

means for reversing the eiect of said differential on said motor; and means responsive to outdoor temperature and eiective as such temperature A passes above and below a chosen value to actuate reversely said reversing means.

5. The combination of means for supplying conditioned air to two zones; means for varying the relative proportions of the total conditioned air delivered to the respective zones; two thermostats, one subject to the temperature in each zone and each including two relatively reversely acting thermostatic elements and selector means to render such elements active selectively; and actuating means for said varying means responsive to the differential between the indications of the thermostats in the two zones. l

6. The combination of means for supplying conditioned air to two zones; means for varying the relative proportions of the total conditioned air delivered to the respective zones; two thermostats, one subject to the temperature in each zone and each including two relatively `reversely acting thermostatic elements and selector means to render such elements active selectively; actuating means for said varyingmeans responsive to the differential between the indications of the thermostats in the two zones; and a common actuating means. for the selector means of the" thermostats in the two tones.v

7. The combination of means for'supplyingy conditioned air to two zones; means'forvarying the relative proportions of the total conditioned air delivered to the respective zones; two thermostats, one subject to the temperature in each zone and each including two relatively reversely acting thermostatic elements and selector means to render such elements active` selectively; actuating means for said varying means responsive to the differential between the indications of the thermostats in the two zones; a common actuating means for the selector means of the thermostats in-the two zones; and means responsive to outdoor temperatureand effective as such temperature passes above and below a chosen value to actuate reversely said `common actuating means. y

8. The combination of means for supplying conditioned air to two zones; means for varying the relative proportions of the total conditioned air delivered to the respective zones; two pneumatic leak port thermostats one subject to the' temperature in each zone, and each including two relatively reversely acting leak controlling thermostatic elements, a supply connection, a branch connection in which control of the leak establishes variable pressure, and means responsive to the pressure in said supply connection for rendering said elements operative selectively; actuating means for said varying means responsive to the differential of pressures in the branch connections of the two thermostats; and means for changing the supply pressure.

9. The'combination of means for supplying conditioned air to two zones; means for varying the relative proportions of the total conditioned air delivered to the respective zones; two Apneumatic leak port thermostats, one sub-ject to the temperature in each zone, and each including two relatively reversely acting leak controlling thermostatic elements; a supply connection; a branch connection in which control of the leak estaby lishes variable pressure, and means responsive to 

